As recalled in the introduction, changing the Schrödinger dynamics, for instance by adding a nonlinear term in the equation,
may introduce the possibility of superluminal signaling [1]}, [2]}, in
contradiction with relativity. A first method
to avoid this problem is to introduce stochasticity into the dynamics: in
this way, the perturbation introduced by the nonlinear term becomes random,
and one can show that it cannot carry messages. This is for example the case in GRW and CSL
theories. The GBC model makes use of a second possibility: the dynamics
remains deterministic, but the random component is introduced by the
initial Bohmian positions of all particles, those of \(S\)  as well as those of \(M\) .
